A flexible electronic device means an electronic device which may bend or crook due to a force applied thereto. This flexible device should have flexibility in itself, and a substrate below the device and a coating layer covering the device should also have flexibility to some extent.
However, a flexible substrate such as plastic may not easily endure a semiconductor manufacturing process which is generally performed in a high-temperature environment. Further, a produced flexible device should have sufficient adhesive force among the substrate, the device and the coating layer, but if the adhesion is insufficient, the substrate, the device and the coating layer may be separated from each other due to bending. In addition, an excellent waterproof property of the coating layer in a fluidic environment, for example in a body, is very important for the flexible electronic device, but a flexible electronic device having a coating layer with a sufficient waterproof property has not yet proposed.
Therefore, there is needed a flexible device packaging technique for transmitting an electric signal generated from a device to the outside while ensuring a waterproof property of the device, protecting the device mechanically and effectively emitting heat even when a large scale integrated circuit (LSI) is formed with a flexible design.